Step 1:Initialization: |
An initial population P is initialized as |
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Where , and , V is the uniform |
distribution function, N is population size, and D is problem |
dimension. represents chromosome in the population P. |
and represents the lower limit upper limit of the solution respectively. |
Step 2: Selection-I: |
In Selection-I, historical population is determined, |
which is used to calculate the direction of search for optimum |
solution. Initial is determined by: |
. |
This process is done through the “if-then” rule as: |
|
Here is defined as update operation, c and d are random |
numbers in the range which help |
decide if the Phis is selected from the former generation. |
After this step the order of the chromosomes is shuffled by |
random shuffling function given by: |
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Step 3: Mutation: |
A mutation is done in to generate a trail population using: |
|
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So, is due to the propagation of chromosomes of in the direction |
set by ( - ) and G controls amplitude of ( - ). Use of gives a |
partial advantage to BSA of the experiences of previous |
population in creating an intelligent trial population . |
Step 4: Crossover: |
It creates the final trial population , the |
initial step towards was set by . Target population is improved |
by chromosomes of having improved fitness. For this crossover uses two |
procedures. First determines a binary matrix map of order. Its |
function is to indicate particles of that are to be changed by using |
relevant particles of . The initial value of is set as 1, |
and trial population is updated as: |
|
Here & . Crossover strategy of |
BSA is presented in Algorithm 2. BSA uses a unique crossover strategy as |
compared to other EAs. The mix-rate parameter controls the number of |
particles that are mutated in atrial by using , is mentioned |
in line of Algorithm 2. This function is the main reason that BSA crossover |
is unique to other EAs |
BSA’s is defined by two predefined strategies being used |
randomly. The first strategy implements mix-rate (Algorithm 2 |
line -), and other allows one chromosome to mutate, chosen |
at random in each trial (Algorithm 2 line -). |
The mutation strategy results in overflow of some particles of |
the PT during crossover procedure. For this, a boundary control |
process is defined that keeps the individual inside the bounds. |
Its algorithm is given in Algorithm 3. |
Step 5: Selection-II: |
In this process the particles of having improved fitness are |
updated by their corresponding better particles of . The global |
minimum and global minimizer are also updated based on the best |
fitness so far. The particle having best fitness is called global |
minimizer denoted by Pbest and its fitness is called global minimum. |
Step 6: Termination |
Finally, optimization process of the BSA is stopped if one the |
following criterion is met: |
(i) Max number of iteration is reached, or |
(ii) The fitness value is below a certain threshold |